This invention relates to the field of electrical wiring, and in particular to devices which facilitate feeding electrical conductors into and through electrical conduit connected to junction boxes or wiring device boxes for electrical outlets and switches.
Prior art devices of this kind include more complex mechanisms to mount to the box or to some other structure, requiring clamps, or separate screws and bolts, and various other kinds of mounting and connecting devices, to mount the quide for the electrical conductor in position for pulling wires through the conduit and box to which the conduit is connected. Also prior art devices which are adapted for use in pulling wires through electrical conduit, generally utilize the mechanical advantage feature of any pulleys that may be used, that is the leverage inherent in the use of a pulley to lessen the manual pulling force required on the part of the workman himself. In order to make use of this inherent mechanical advantage of pulleys it is necessary to mount the pulley rigidly to the box or some structure near the box. Thus, the prior art devices of this kind include rigid mounting or positioning means, even if they may be used occasionally at the opposite end of the conduit for feeding wires into the conduit in addition to being used for pulling wires out of the conduit.
It does not appear to have occurred to anyone to provide a special guide, such as a guide roller, for the exclusive purpose of feeding electrical conductors into electrical conduit in which the case the guide does not have to be rigidly mounted since no leverage or mechanical advantage is available in any event at the trailing end of the conduit and wire.
The advantage of not having to mount the guide, such as a roller guide, rigidly is that it can be mounted rapidly, almost instantaneously by simply hooking into one or two of the already existing apertures on junction boxes or by simply and quickly hooking on to the already existing screws of wiring device boxes, sometimes called outlet boxes, for electrical outlets and electrical switches. An electrician can thus with the present invention, quickly hook the guide, such as a roller guide, to the junction or outlet box at the feed-in side with the conductors or wires in place on the roller (or other guide) and fed through the conduit with the end of the leader or pull-through wire projecting out the other end of the conduit, then move to the pull-through side and begin pulling the wires through. The roller or other guide in accordance with this invention keeps the wires from kinking, scraping or catching at the feed-in side, so a separate workman is not needed at that end a single workman can thus draw the wires through without damage from scraping, catching or kinking at the feed-in side.
Examples of prior art devices are disclosed in U.S. Pat. Nos. 4,358,089; 4,033,551; 3,944,184; 3,113,759; 2,746,715; and 2,727,721. All of these disclose rigidly mounted, or rigidly held guides or pulleys so they can be used either exclusively for pulling wires through, or for pulling as well as feeding wires through electrical conduit. None appear to be exclusively for feeding wires into the conduit, and they accordingly do not have the quick-connect or quick-mount feature of the present invention. Time is such an essential factor in electrical wiring that this feature alone of the present invention is of great value.